Oki C9300dn User Manual page 25

Insert each toner cartridge into its image drum, left side first,
3.
engaging the drum locating peg in the hole in its toner
cartridge. Make sure the colours of the toner cartridge and
image drum correspond.
Gently push the toner cartridge down, engaging the locking
4.
pin into the groove on the image drum.
SETTING UP > 25